Dina, I know how you feel.
My Lucky is much bigger than Pia, he weighs 11 lbs and the last vet visit, he suggested we have Lucky's teeth cleaned. I'm like you, VERY scared to have him put under. The only suggestion I have is I recently bought PetzLife, Oral Care for dogs. Mine is a spray that is supposted to keep their teeth white and healthy. I found this out from Archie on here. She uses it on Buddy and his teeth look great.
Good Luck in deciding what to do. It's a hard decision.